This is a good article to post to our new Facebook site for the book – “Beyond Genius…”

– Scott

University of Minnesota

Sherlock Holmes, the self-proclaimed world’s only consulting detective, is the paragon of clever reasoning, famous for startling leaps of inference. Any of his appurtenances—the deerstalker hat, the pipe, the magnifying glass—is enough to evoke observation and cool-headed rationality. And, despite his singular occupation, he offers a lesson for the rest of us on the uses of scientific thinking in everyday life.

Arthur Conan Doyle draws readers into the process of detection with what his biographer John Dickson Carr called “enigmatic clues.” Holmes signposts a piece of evidence as significant but doesn’t immediately reveal its use, leaving it as an exercise for the reader. “The creator of Sherlock Holmes invented it,” Carr wrote in 1949, “and nobody … has ever done it half so well.” In one of the most celebrated examples, Sherlock Holmes quizzes a client about the “curious incident of the dog in the night-time.” “The dog did nothing in the night-time,” the man says. “That was the curious incident,” remarks Holmes.

Spectacular detective An illustration by Frederic Dorr Steele that accompanied the 1904 publication of ‘The Adventure of the Golden Pince-Nez’ in Collier’s magazine.

Holmes’s supreme rationality is of a piece with his interest in science. “The Scientific Sherlock Holmes,” by James O’Brien, an emeritus professor of chemistry at Missouri State University, explores the forensic methods and scientific content in the Holmes canon as well as his creator’s own scientific background. Born in 1859, Conan Doyle took to books at the encouragement of his mother. Frustrated by the rigidity of his Catholic schooling, he moved toward science. At 17, he began medical school in Edinburgh. There his mentor was Dr. Joseph Bell, a man with sharpened diagnostic abilities who would serve as a model for Holmes. In one instance, Bell gleaned that a woman who had come in with her child was from the town of Burntisland (her accent), had traveled via Iverleith Row (red clay on shoes), had another child (a too-large jacket on the one present) and worked at a linoleum factory (dermatitis on fingers).

After his schooling, Conan Doyle’s rich uncles offered to set him up with wealthy Catholic patients in London, but he sacrificed the opportunity by proclaiming that he was now agnostic. His first tax return, listing an income of £154, was mailed back to him with a note: “Not satisfactory.” He returned it with an addendum: “I agree entirely.

Lack of patients gave Conan Doyle time to focus on fiction. His greatest influence was Edgar Allen Poe, who had invented detective stories in the 1840s. Poe’s protagonist, C. Auguste Dupin, was, like Holmes, a clever eccentric with a narrator sidekick and a dim police force as his foil. But Conan Doyle saw room to improve: “I had been reading some detective stories, and it struck me what nonsense they were, to put it mildly, because for getting the solution to the mystery the authors always depended on some coincidence.” So came his heavy reliance on science, as well as those enigmatic clues. He published the first of his 60 Holmes stories in 1887, and by the third he was boosting sales of the magazine that ran them by 100,000 copies per issue. People were hungry for the stuff.

Mr. O’Brien spends most of his slim book, a volume most suitable for those already fond of Sherlock and not afraid of section titles with catchy names like “Section 4.2,” exploring the various fields that Holmes draws on—principally chemistry, with a little biology and physics. We learn about the use of coal-tar derivatives and handwriting identification in both Holmes’s world and ours. Some techniques, such as fingerprinting, appeared in the stories even before they were widely adopted by real police.

Mr. O’Brien is particularly interested in the question of how good a scientist Holmes actually was. Isaac Asimov, who was a biochemist as well as a science-fiction writer, called Holmes a “blundering chemist,” alleging slips in terminology and in the identification of gems. Mr. O’Brien defends his man in detail, concluding that Holmes the chemist falls “somewhere between Watson’s ‘profound’ and Asimov’s ‘blundering.’ ‘Eccentric’ sounds just about right.”

Conan Doyle went out of his way to place science in the stories, even if merely as set decoration. In one, Holmes and Watson discuss the Earth’s axial tilt after tea. But more than any particular discipline, he focused on the value of a scientific mindset. At one point, Holmes tells Watson: “It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts.” When, in the second half of the canon, science begins to fall by the wayside, the stories suffer. Mr. O’Brien argues (non-scientifically but plausibly) that this correlation indicates causation: “The science lends a robustness and occasional complexity to the stories which contributes to their authenticity and provokes thought in the reader.” A detective tale that doesn’t place demands on the reader is a dog that just won’t hunt (or bark).

Another look at the cogs under the deerstalker is offered by “Mastermind: How to Think Like Sherlock Holmes,” by Maria Konnikova, a psychology graduate student at Columbia University. Following Holmes’s metaphor of the “brain attic,” she describes how Holmes stocks his attic (observation), explores it (creativity), navigates it (deduction) and maintains it (continuing education and practice). In the process, she lays out the habits of mind—both the techniques Holmes employs and the errors he avoids—that we might usefully emulate.

Much of the material will be familiar to readers acquainted with Daniels such as Ariely, Kahneman and Gilbert (“Predictably Irrational,” “Thinking Fast and Slow,” “The How of Happiness”). The availability heuristic, the halo effect, confirmation bias: Your favorite mental short-cuts and slip-ups are all here. But Ms. Konnikova finds an ingenious delivery system. Holmes and Watson, she shows, respectively personify our rational and intuitive modes of thought. In story after story, taking the time to think carefully allows Holmes to school his slack-jawed sidekick.

Scientific thinking is not just for scientists or detectives. In almost any domain, it’s a good idea to frame a problem well, research it thoroughly, conjure a hypothesis, test it and repeat as necessary. In a chapter called “We’re Only Human,” Ms. Konnikova details how Conan Doyle himself lost his way. After years as an agnostic, he dove into spiritualism, even “verifying” several photographs of fairies. We believe what we want to believe.

Ms. Konnikova’s thoughtful book duly put me in a Holmesian mindset in which I spied a few minor mistakes in the science (she at one point says only one side of the brain processes visual input), but overall she covers a wide variety of material clearly and organizes it well.

It’s worth mentioning one scientific idea that Holmes does not explicitly touch on: that of testability. In 1934 the philosopher Karl Popper persuasively argued that, to be scientific, a claim must be falsifiable; if no conceivable piece of evidence could ever invalidate it, then the claim is compatible with literally any observation you might potentially make and so is useless for forming concrete predictions. Some Sherlock scholars seem to have missed the boat on this one. Mr. O’Brien writes that “Sherlockians have a tendency never to blame Holmes” for his occasional flubs. He once calls 29 inches of mercury a “very high” barometric pressure; one Holmesian suggested that the low air pressure went to his head. If nothing else, you can always blame Watson for misquoting him. Holmes’s hallowed infallibility is thus non-falsifiable. Which goes to show that a regard for tales of ratiocination does not preclude a capacity for faith.